/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.pig.piggybank.evaluation.string;

import java.io.IOException;

import org.apache.pig.EvalFunc;
import org.apache.pig.data.DataAtom;
import org.apache.pig.data.Tuple;
import org.apache.pig.impl.logicalLayer.schema.Schema;
import org.apache.pig.impl.logicalLayer.schema.AtomSchema;

/**
 * string.UPPER implements eval function to convert a string to upper case
 * Example:
 *      register pigudfs.jar;
 *      A = load 'mydata' as (name);
 *      B = foreach A generate string.UPPER(name);
 *      dump B;
 */
public class UPPER extends EvalFunc<DataAtom>
{
    /** 
        * Method invoked on every tuple during foreach evaluation
        * @param input tuple; first column is assumed to have the column to convert
        * @param output - resulting value
        * @exception IOException
                                                           */
    //@Override
    public void exec(Tuple input, DataAtom output) throws IOException {
        String str = input.getAtomField(0).strval();
        output.setValue(str.toUpperCase());
    }

    //@Override
    /**
     * This method gives a name to the column. 
     * @param input - schema of the input data
     * @return schema of the input data
     */
    public Schema outputSchema(Schema input) {
        return new AtomSchema("upper_" + input.schemaFor(0).toString()); 
    }
}
